1. Field
An aspect of the present invention relates to a disk management device, a storage system and a disk management method that manage data writing to and data reading from a disk drive. An aspect of the present invention may include a disk management device, a storage system and a disk management method in which a disk drive and a disk management device manage data in different control units.
2. Description of the Related Art
Recently, the capacity of recording media has been increased by a technique in which accesses to multiple disk drives are managed collectively by a disk management device. Typically, the storage systems have an error-correcting function to achieve greater levels of reliability.
Japanese Laid-open Patent Publication 2006-268673 discloses a technique in which all sectors subsequent to an incomplete-write sector are checked for errors when writing a series of data onto multiple sectors has failed and been suspended is known.
Japanese Laid-open Patent Publication 2006-31332 discloses a technique in which disk drives have a redundant configuration is also known. Losses of data in a disk drive are checked and recovered in a check process to restore the redundancy.
Conventional storage systems use a Fiber Channel (FC) disk or a Serial Attached SCSI (SAS) disk. The FC disk and the SAS disk are partitioned by 520-byte block-512 bytes for data and 8 bytes for block check character. Data stored on the disks are managed by logical block addresses (LBA) assigned to each block. Thus, the disk management device controls accesses to the disk with LBAs assigned to each 520-byte block as well.
There has been a demand of realizing a technique in which the disk management device managing data with the 520-byte control unit manages disks on which data are managed with LBAs assigned to 512-byte blocks, such as a SATA disk. Managing disks on which data are managed in different control units may reduce costs on an entire system by utilizing inexpensive disks in parallel with utilizing conventional management device configuration.
However, where data stored on the disks and in the disk management device are managed in different control units, LBAs assigned to the disks may be inconsistent with LBAs assigned to the disk management device. Data are recovered based on the LBA when an error occurs. However the inconsistency may contribute to loss of data in an error correction process.